Switching to GFP_ATOMIC is the worst of all possible ways of "fixing"
this bug. GFP_ATOMIC is *unreliable*. We don't want to introduce
unreliability deep down inside our filesytems. And fs maintainers who
don't want to make their filesystems less reliable shouldn't blindly
apply patches that do so :(
A reliable way of fixing this bug is below. As an added bonus, it
makes the fs faster.
--- a/fs/ocfs2/dlm/dlmdomain.c~a
+++ a/fs/ocfs2/dlm/dlmdomain.c
@@ -926,9 +926,9 @@ static int dlm_assert_joined_handler(str
}
static int dlm_match_regions(struct dlm_ctxt *dlm,
- struct dlm_query_region *qr)
+ struct dlm_query_region *qr, u8 *local)
{
- char *local = NULL, *remote = qr->qr_regions;
+ char *remote = qr->qr_regions;
char *l, *r;
int localnr, i, j, foundit;
int status = 0;
@@ -957,12 +957,6 @@ static int dlm_match_regions(struct dlm_
r += O2HB_MAX_REGION_NAME_LEN;
}
- local = kmalloc(sizeof(qr->qr_regions), GFP_ATOMIC);
- if (!local) {
- status = -ENOMEM;
- goto bail;
- }
-
localnr = o2hb_get_all_regions(local, O2NM_MAX_REGIONS);
/* compare local regions with remote */
@@ -1012,8 +1006,6 @@ static int dlm_match_regions(struct dlm_
}
bail:
- kfree(local);
-
return status;
}
@@ -1077,6 +1069,7 @@ static int dlm_query_region_handler(stru
struct dlm_ctxt *dlm = NULL;
int status = 0;
int locked = 0;
+ static u8 local[sizeof(qr->qr_regions)]; /* locked by dlm_domain_lock */
qr = (struct dlm_query_region *) msg->buf;
@@ -1112,7 +1105,7 @@ static int dlm_query_region_handler(stru
goto bail;
}
- status = dlm_match_regions(dlm, qr);
+ status = dlm_match_regions(dlm, qr, local);
bail:
if (locked)